I was having to dust my desk area every couple of days- it was so gross how quickly things would build up! Now, I am down to dusting my desk once every week and a half. I'm quite allergic to dust, so I know that this is making an improvement on my health since I spend at least 8 hours per day in my office. It has easy presets for 1, 2, 4, or 8 hours. I plan to get larger units for my bedroom and living room to provide 24-hour support for wherever I am in the house.